Radio frequency identification (RFID) systems are generally known and may be used for a number of applications such as managing inventory, electronic access control, security systems, automatic identification of cars on toll roads, and electronic article surveillance (EAS). RFID devices may be used to track or monitor the location and/or status of articles or items to which the RFID devices are applied. A RFID system typically comprises a RFID reader and a RFID device such as a tag or label. The RFID reader may transmit a radio-frequency carrier signal to the RFID device. The RFID device may respond to the carrier signal with a data signal encoded with information stored on the RFID device. RFID devices may store information such as a unique identifier or Electronic Product Code (EPC) associated with the article or item.
RFID devices may be programmed (e.g., with the appropriate EPC) and applied to the article or item that is being tracked or monitored. A RFID reader/programmer may be used to program RFID devices and to detect defective RFID devices. Label applicators have been used to apply programmed RFID labels to items or articles.
Existing RFID applicators, however, have encountered problems in handling defective labels. In existing RFID applicators, a RFID reader/programmer may be located upstream from the applicator. One problem occurs when tracking a defective label from the point at which it is detected to the point at which it can be rejected. Because of potential differences in the RFID label footprints and web paths through the applicator, the number of labels between the point of detection and the point of rejection may be inconsistent. As a result of this inconsistency, an applicator may reject a good label and may apply a defective label to the product.
Another problem is that the rejection of defective RFID labels may interrupt the label application process and may result in labels not being applied to items or products. When a defective label is detected using conventional techniques, it may be removed from the process and another label may be re-encoded in its place. Each defective label that is encountered may cut the product application rate by up to an additional 50%. Product lines may need to be run slower so as not to miss a product in the event a defective label is detected.